Which province or city has the most district-level administrative units in Vietnam?

Long An and Kien Giang are the two provinces in the Mekong Delta region with the most district-level administrative units, with 15 cities/towns/districts.

Long An has 1 city, 1 town, 13 districts.

City: Tan An

Town: Kien Tuong

13 districts: Duc Hoa, Can Giuoc, Can Duoc, Ben Luc, Chau Thanh, Thu Thua, Tay Thanh, Tan Tru, Duc Hue, Thanh Hoa, Tan Hung, Vinh Hung, Moc Hoa.

Kien Giang also has 15 district-level administrative units, including 3 cities and 12 districts.

3 cities: Rach Gia, Phu Quoc, Ha Tien

12 districts: Giong Rieng, Chau Thanh, Hon Dat, Go Quao, Tan Hiep, An Minh, An Bien, Vinh Thuan, Kien Luong, U Minh Thuong, Giang Thanh, Kien Hai.